Pneumatic feed system for uniform supply of tobacco to cigarette making machines

ABSTRACT

A tobacco discharger associated with a cigarette making machine and an automatic tobacco conveying system for pneumatically conveying tobacco from a storage area to the cigarette machine wherein the conveying system includes a main feed pipe coupled with the source of the stored tobacco and the discharger, air differential pressure means for forcing air through the pipe at a predetermined conveying velocity, a tobacco feeder at the source of stored tobacco for feeding the tobacco into the main feed pipe, and air pressure sensitive means for sensing the air pressure in the main pipe and actuating the operation of the feeder upon attainment of the predetermined conveying velocity of the air to the discharger. The discharger includes a housing having an air inlet end coupled with the main feed pipe and an air discharge end. It also contains tobacco separating means within the housing for separating tobacco carried by air entering the inlet end so that the separated tobacco is uniformly distributed within the housing. Means are also included for causing the uniformly separated tobacco to be discharged into the cigarette making machine in a constantly uniform manner due to the uniform positioning of the separated tobacco within the housing.

United States Patent Primary Examiner-Andres I-I. Nielsen Attorney-Kane,Dalsimer, Kane, Sullivan and Kurucz 2-11 Appl. No.

Filed Mar. 4, 1969 ABSTRACT: A tobacco discharger associated with acigarette [45] Patented May25,l971

Assignee making machine and an automatic tobacco conveying system Brown& Williamson Tobacco Corporation Louisville, Ky.

for pneumatically conveying tobacco from a storage area to the cigarettemachine wherein the conveying system includes a main feed pipe coupledwith the source of the stored tobacco and the discharger, airdifferential pressure means for forcing air through the pipe at apredetermined conveying velocity, a tobacco feeder at the source ofstored tobacco for [54] PNEUMATIC FEED SYSTEM FOR UNIFORM f SUPPLY OFTOBACCO To CIGARETTE MAKING ceding the tobacco into the main feed pipe,and air pressure MACHINES sensitive means for sensing the air pressurein the main pipe 2 Claims, 2 Drawing Figs and actuating the operation ofthe feeder upon attainment of [52] U 8 Cl the predetermined conveyingvelocity of the air to the discharger. The discharger includes a housinghaving an air inlet end coupled with the main feed pipe and an airdischarge end. It also contains tobacco separating means within thehousing for separating tobacco carried by air entering the inlet [50]Field of end so that the separated tobacco is uniformly distributedwithin the housing. Means are also included for causing the uniformlyseparated tobacco to be discharged into the cigarette making machine ina constantly uniform manner due 302/59 to the uniform positioning of theseparated tobacco within the 302/28 housing.

Smm mm Nn" mm Tn" mm Pu mh ASd T w m D WGB mm 99 n 06 03 47 36 38 3PNEUMATIC FEED SYSTEM FOR UNIFORM SUPPLY OF TOBACCO TO CIGARETTE MAKINGMACHINES CROSS REFERENCE TO RELATED APPLICATIONS Reference is made to myprevious U.S. Pat. No. 3,386,773 issued on June 4, 1968 for PneumaticFeed System For Cigarette Making Machines, the subject matter of whichis incorporated herein by reference.

BACKGROUND OF THE INVENTION Initially it should be noted that the abovementioned patent provided a significant contribution to the art ofcigarette manufacturing by providing a significantly improved pneumaticfeed system for cigarette making machines. Naturally as the art advancesfurther developments are made in this area and it is a furtherimprovement for use with a system of the type described in the abovepatent with which this disclosure is concerned.

It has been observed in certain instances where a pneumatic feed systemin accordance with the above patent is being used that, even though thedifferential pressure sensing device was properly adjusted and thedischarger units were filling properly, there existed a definitetendency for the making machine hopper to fill unevenly. This unevennessfollowed a very definite pattern with the underfill always occurring onthe side of the hopper beneath the tobacco and air combination inletside of the discharger. Study of this phenomenon has revealed that thisis a function of the system itself even though everything is adjustedproperly. To retrogress a moment, to properly understand and explainthis uneven filling, one must first understand the manner in which adischarger separates the tobacco from the air stream and the manner inwhich the separating chamber fills. When the suction valve opens, airdrawn through the discharger first closes the discharger door and thenstarts drawing air through the feed pipe. When conveying velocity isreached, the tobacco feeder starts and tobacco is fed into the system.The first tobacco, separated by the screen and air currents in thedischarger, is deposited in the lower comer of the separating chamber onthe side beneath the air discharge. The filling then proceeds atapproximately a 45 angle toward the feed end of the discharger. When thedifferential pressure sensing unit stops the cell on the system, thechamber is approximately 95 percent full. To fill this last 5 percent ofthe chamber, the probability of blocking the check valve becomes aproblem. Therefore it is preferable not to even attempt to completelyfill the chamber.

The 5 percent empty area coupled with the compressive packing of thefirst tobacco separated, caused by the air velocity and weight of thematerial as it is progressively deposited across the width of thedischarger, are the factors causing the uneven hopper filling beneaththe tobacco and air inlet end of the discharger. Due to the manner inwhich the making machine feeds cut tobacco from the hopper onto thecigarette forming feed belt, a nonuniformity in the hopper level causesa periodic noncontrollable low density spot in the continuous cigaretterod formed on the machine. This light spot is then sensed by the weightcontrols on the machine causing them to put out a correction forsomething that it cannot correct and thereby possibly further upsettingthe weight control of the machine. Thisall contributes to a greaternonuniformity in the cigarette weights which are a quality concern.Therefore, although the system of the above patent has provided a greatcontribution to the art, to compensate for this additional newlydiscovered problem, it would be helpful if a means could be provided inthe system for alleviating this particular drawback.

SUMMARY OF THE INVENTION ing area from the air discharge side to thetobacco and air inlet side. The sloping of the screen has greatlyincreased the uniformity of the feed roll in the making machine hopperand eliminated the uneven filling on a properly adjusted system.

In summary, the general concept embodied in this invention is to providean improved tobacco discharger associated with a cigarette makingmachine and an automatic tobacco conveying system for pneumaticallyconveying tobacco from a storage area to the cigarette machine whereinthe conveying system includes a main feed pipe coupled with the sourceof the stored tobacco and the discharger, air differential pressuremeans for forcing air through the pipe at a predetermined conveyingvelocity, a tobacco feeder at the source of stored tobacco for feedingthe tobacco into the main feed pipe, and air pressure sensitive meansfor sensing the air pressure in the main pipe and actuating theoperation of the feeder upon attainment of the predetermined conveyingvelocity of the air to the discharger. The discharger includes a housinghaving an air inlet end coupled with the main feed pipe and an airdischarge end. It also contains tobacco separating means within thehousing for separating tobacco carried by air entering the inlet end sothat the separated tobacco is uniformly distributed within the housing.Means are also included for causing the uniformly separated tobacco tobe discharged into the cigarette making machine in a constantly uniformmanner due to the uniform positioning of the separated tobacco withinthe housing.

With the above and other objects in mind, reference is had to theattached drawing of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a longitudinal sectional view of the novel tobacco separatorof the system for pneumatically conveying cut tobacco from a storagearea to a cigarette making machine of this invention associated with thehopper of a cigarette making machine; and

FIG. 2 is a sectional view thereof taken along the line 2-2 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT So that the structure andoperation of the majority of the system is identical to that of theabove referenced patent application, a detailed picture of the commonelements is not necessary nor is it necessary to include a detaileddescription of these elements. The difference in structure lies in thetobacco discharger portion of the system and it is that portion which isdepicted in FIGS. 1 and 2 and which will be described in detail below.

However, to put the tobacco discharger in its proper environment, ageneral overall .description of the system will be included herein toorient that reader as to the particular location and function of theunique subject matter within the overall system as particularly definedin the above referenced patent. The overall purpose of the pneumaticsystem of the invention is to convey cut tobacco from the cut tobaccostorage areas to the making machines automatically, as required by themaking machines. A sensing device in each making machine hopper operatesto detect a low level of tobacco to initiate the prescribed series ofevents. The system is designed to feed only one of a given number ofmaking machines at a time upon request for cut tobacco.

When a request is made by a particular cigarette making machine, acontrol unit operates to select the proper making machine and opens thesuction side of a separator incorporating the teachings of the presentinvention, located at the top of the selected making machine hopper. Atthe same time, the control unit initiates a cycle timing device.Thereafter, a trapped door on the tobacco separator is drawn closed andcheck valves on all of the other separators in the system are closed anddrawn into their respective seats by the suction valve present in thetobacco feed pipe. Air flow is now established in the system from thecut tobacco to the exhaust of the suction producing device through theselected separator of the making machine requiring tobacco.

When the air flow in the feed pipe or duct reaches the prescribedconveying velocity, a differential pressure switch located in proximityof the feeder senses this condition and causes the feeder to beenergized independently and without any connection to the balance of thesystem other than the feed pipe. Tobacco flow is now established betweenthe storage area and the selected making machine. At the particularseparator, the tobacco is separated from the air stream by means of ascreen installed between the inlet and discharge and of the separator.

As the air conveyed cut tobacco fills the separator, the pressure dropacross the separator progressively increases. When this pressure dropreaches a preset level or value, the control unit closes the suctionside of the separator. The desired amount of cut tobacco collected onthe separator screen is correlated to pressure drop to thereby assurethe optimum amount of tobacco to be loaded into the selected cigarettemaking hopper, with the cycle timing device operating to serve as asafety factor in preventing overloading of the separator.

The loss of conveying velocity in the feed pipe will now be sensed bythe differential pressure switch located near the feeder to therebycause deenergization of 'the feeder. The trapped door of the separatorwill now swing open under the influence of gravity and the collected cuttobacco falls into the selected making machine hopper. When this occurs,the low level circuit on the making machine is deenergized. Provision ismade in the control unit to prevent an immediate recall on a makerbefore the tobacco drops into the hopper in the event there is no othermaker with a low level indicated.

Also contemplated is a control unit set up either on a random memorynetwork or a sequential demand network. In any event, the master controlunit is at rest when no maker is showing a low level.

In addition, controlled air bleeds are incorporated into the feed lineof the last maker located on the feed line to prevent an accumulationtype buildup which eventually might cause a stop-up in the system. Acontrolled air bleed in the suction line 1 of the blower is used insystems where multiple feed systems are taken off a single blower. Thisair bleed is controlled by the motor load to prevent the blower frompulsating on no load conditions by bleeding air into the system and fromoverloading on full load conditions by closing off the air bleed.

In addition to the above general reiteration of the improved system forconveying cut tobacco from a storage area to a cigarette making machineas defined particularly in the above referenced patent, details of thecut tobacco separator associated with each making machine hopper are ofa novel and improved nature which will be disclosed in considerabledetail as follows. Referring now to the particular details of the novelseparator 20, the separator is advantageously mounted over the hopper 21of a cigarette making machine only fragmentarily shown in the drawings.This machine may assume the form of any one of a number of commerciallyavailable cigarette making machines. When necessary, hopper 21 ofcommercial equipment may require that its capacity be decreased. Be thatas it may, hopper 21 includes Sonac relay sensors (not shown) or othersuitable means for responding to the level of tobacco in the hopper toregister the call or request for tobacco from the pneumatic conveyingsystem of the invention. When this occurs, cut tobacco will eventuallyenter the separator 20 through the check valve 22 and fill thecompartment 23 immediately below the separating screen 24 with the airstream passing on through the open suction valve 25. When thecompartment 23 is nearly full, screen 24 is very nearly blocked therebycausing a relatively high differential pressure across the screen.Advantage is taken of the develop-' ment of this pressure drop byemploying a differential pressure switch 26 communicating with both theupstream and downstream side of the separator and across screen 26. Uponthe attainment of the desired predetermined pressure drop or pressuredifferential, switch 26 is actuated to cause the suction valve 25 to beclosed. Subsequently, the trap or discharge door 27 at the base ofseparator 20 will open and release the accumulated tobacco into thecigarette making machine hopper 21. The check valve 22, in accordancewith a success ful and somewhat preferred embodiment of the invention,embodies a soft, tough, resilient material contained between a pair ofmetal discs. The small disc is merely a retainer for holding the largerouter discs. In the closed position, valve 22 is sucked into the inletend 28 of the feed pipe and will close and seal over any particles oftobacco that may be found on the valve seat, thereby preventing anybackfl ow air leakage. The suction valve 25 is shifted from a fullyopened to fully closed position by means of a piston cylinder 29.Cylinder 29 operates preferably off a four-way solenoid air valve (notshown).

Particular attention should be paid to separator screen 24 which issloped upwardly in location in separator 20. The lower side of screen 24is adjacent the discharge passage of the separator and the upper side ofscreen 24 is adjacent the inlet passage. As previously described indetail, this is necessary in order to achieve a particular uniformdistribution of tobacco within the separator 20 which is later to bedischarged through discharge door 74 into the cigarette making machine.This positioning of screen 24 is advantageous due to the tendency forthe separator to fill unevenly. This is true even though thedifferential pressure sensing device is properly adjusted and thedischarging unit is filling properly. With a horizontal screen, theuneveness will follow a very definite pattern with the underfill alwaysoccurring on the side of the hopper beneath the tobacco and air inletside of the separator 20.

As previously discussed, observation of this phenomenon has revealedthat this will occur with a horizontal screen even though everything isadjusted properly. To explain this uneven filling, one must firstunderstand the manner in which a discharger separates the tobacco fromthe air stream and the manner in which the separating chamber fills.When the suction valve 25 opens, air drawn through the discharge firstcloses the discharge door 27 and then starts drawing air through thefeed pipe. When conveying velocity is reached, the tobacco feeder startsand tobacco is fed into the system. The first tobacco, separated by ahorizontal type of screen and air currents in the separator, isdeposited in the lower corner of the separating chamber on the sidebeneath the air discharge. The filling then proceeds at approximately a45 angle toward the feed end of the separator. When the differentialpressure sensing unit stops the call on the system, the chamber isapproximately percent full. To fill this last 5 percent of the chamber,the probability of blocking the check valve 22 becomes a problem.Therefore, it is generally not ever attempted to completely fill thechamber.

The 5 percent empty area coupled with the compressive packing of thefirst tobacco separated, caused by the air velocity and weight of thematerial as it is progressively deposited across the width of theseparator, are factors contributing to the uneven hopper filling beneaththe tobacco and air inlet ends 76 of the separator 20. Due to the mannerin which the making machine feeds cut tobacco from the hopper onto thecigarette forming feed belt, a nonuniformity in the hopper level causesa periodic noncontrollable low density spot and the continuous cigaretterod formed on the machine. This light spot is then sensed by the weightcontrols on the machine causing them to put out a correction forsomething that it cannot correct and thereby further upsetting theweight control of the machine. This all contributes to a greaternonuniformity in cigarette weights which are a major quality concern. Tocompensate for this, separating screen 24 in separator 20 has beenraised on the inlet side. This provides a progressively increasing areafrom the air discharge side to the tobacco and air inlet side.

Thus, sloping of screen 24 has greatly increased the uniformity of thefeed roll in the making machine hopper and has virtually eliminated theoccurrence of uneven filling on a properly adjusted system.

Thus, the above mentioned objects of the invention, among others, areachieved.

lclaim:

1. An automatic tobacco conveying system for pneumatically conveyingtobacco from a storage area to at least one cigarette making machine,said system including a main feed pipe coupled with the source of thestored tobacco and the cigarette making machine, a tobacco dischargerassociated with said cigarette making machine and having a housing withan inlet coupled with the main feed pipe and an air discharge end andmeans for causing the separated tobacco to be discharged into thecigarette making machine, air differential pressure means for forcingair through the pipe at a predetermined conveying velocity, a tobaccofeeder at the source of stored tobacco for feeding the tobacco into themain feed pipe, and air pressure sensitive means for sensing the airpressure in the main pipe and actuating the operation of the feeder uponattainment of the predetermined conveying velocity of the air to thecigarette making machine, the improvement comprising: tobacco separatingmeans within the housing for separating tobacco carried by air enteringthe inlet in a uniform manner so that the separated tobacco isdistributed uniformly within the housing so that when the separatedtobacco is discharged into the cigarette making machine it will bedischarged in a uniform manner, said tobacco separating means in saidhousing including a tobacco separating screen arranged within thehousing intermediate the inlet and discharge ends which are located onopposing sides of the housing for separating tobacco carried by airentering the inlet end, said separating screen being sloped angularlyupward from the discharge end side of the housing toward the inlet endside of the housing thereby providing a progressively increasing areabeneath the screen within the housing from the air discharge side to theair inlet side to assist in providing uniform discharge of the tobaccointo the cigarette making machine.

2. A tobacco discharger associated with a cigarette making machine andan automatic tobacco conveying system for pneumatically conveyingtobacco from a storage area to the cigarette making machine with thesystem including a main feed pipe coupled with the source of the storedtobacco and the tobacco discharger, air differential pressure means forforcing air through the pipe at a predetermined conveying velocity, atobacco feeder at the source of stored tobacco for feeding the tobaccointo the main feed pipe, air pressure sensitive means for sensing theair pressure in the main pipe and actuating the operation of the feederupon attainment of the predetermined conveying velocity of the air tothe tobacco discharger comprising; a housing having an air inlet andcoupled with the main feed pipe and an air discharge end, tobaccoseparating means within the housing for separating tobacco carried byair entering the inlet end in a manner which distributes the tobaccowithin the housing in a uniform manner, and means for causing theuniformly distributed separated tobacco to be discharged into thecigarette making machine in a manner which greatly alleviates the dangerof uneven filling during the following cigarette making process, thetobacco separating means including a tobacco separating screen arrangedwithin the housing intermediate the inlet and discharge ends which arelocated on opposing sides of the housing for separating tobacco carriedby air entering the inlet end, said screen sloping upwardly fromadjacent the discharge end of the housing toward the inlet end of thehousing thereby uniformly separating and distributing tobacco carried byair entering the inlet end within the housing to greatly increase theuniformity of the separated tobacco within the housing to be dischargedinto the cigarette making machine.

1. An automatic tobacco conveying system for pneumatically conveyingtobacco from a storage area to at least one cigarette making machine,said system including a main feed pipe coupled with the source of thestored tobacco and the cigarette making machine, a tobacco dischargerassociated with said cigarette making machine and having a housing withan inlet coupled with the main feed pipe and an air discharge end andmeans for causing the separated tobacco to be discharged into thecigarette making machine, air differential pressure means for forcingair through the pipe at a predetermined conveying velocity, a tobaccofeeder at the source of stored tobacco for feeding the tobacco into themain feed pipe, and air pressure sensitive means for sensing the airpressure in the main pipe and actuating the operation of the feeder uponattainment of the predetermined conveying velocity of the air to thecigarette making machine, the improvement comprising: tobacco separatingmeans within the housing for separating tobacco carried by air enteringthe inlet in a uniform manner so that the separated tobacco isdistributed uniformly within the housing so that when the separatedtobacco is discharged into the cigarette making machine it will bedischarged in a uniform manner, said tobacco separating means in saidhousing including a tobacco separating screen arranged within thehousing intermediate the inlet and discharge ends which are located onopposing sides of the housing for separating tobacco carried by airentering the inlet end, said separating screen being sloped angularlyupward from the discharge end side of the housing toward the inlet endside of the housing thereby providing a progressively increasing areabeneath the screen within the housing from the air discharge side to theair inlet side to assist in providing uniform discharge of the tobaccointo the cigarette making machine.
 2. A tobacco discharger associatedwith a cigarette making machine and an automatic tobacco conveyingsystem for pneumatically conveying tobacco from a storage area to thecigarette making machine with the system including a main feed pipecoupled with the source of the stored tobacco and the tobaccodischarger, air differential pressure means for forcing air through thepipe at a predetermined conveying velocity, a tobacco feeder at thesource of stored tobacco for feeding the tobacco into the main feedpipe, air pressure sensitive means for sensing the air pressure in themain pipe and actuating the operation of the feeder upon attainment ofthe predetermined conveying velocity of the air to the tobaccodischarger comprising; a housing having an air inlet and coupled withthe main feed pipe and an air discharge end, tobacco separating meanswithin the housing for separating tobacco carried by air entering theinlet end in a manner which distributes the tobacco within the housingin a uniform manner, and means for causing the uniformly distributedseparated tobacco to be discharged into the cigarette making machine ina manner which greatly alleviates the danger of uneven filling duringthe following cigarette making process, the tobacco separating meansincluding a tobacco separating screen arranged within the housingintermediate the inlet and discharge ends which are located on opposingsides of the housing for separating tobacco carried by air entering theinlet end, said screen sloping upwardly from adjacent the discharge endof the housing toward the inlet end of the housing thereby uniformlyseparating and distributing tobacco carried by air entering the inletend within the housing to greatly increase the uniformity of theseparated tobacco within the housing to be discharged into the cigarettemaking machine.